1. Field of the Invention
The present invention relates to a variable speed power transmission apparatus which is applied to rotating machines such as drivers for driving a blower, pump, compressor, centrifugal separator, stirrer, mill, excavator, cutter machine, polishing machine, winch, crane hoister and automobile collision tester and which is intended to be used for making variable the output rotations number of the rotating machine.
2. Description of the Related Art
While almost all rotating machines such as drivers for driving a blower, pump, compressor, centrifugal separator, stirrer, mill, excavator, polishing machine, winch, crane hoister and automobile collision tester have each been used with their fixed rotations number, when using each of these rotating machines with the output rotations number thereof being kept variable, the following means have hitherto been adopted.
(1) Use is made of a rotating machine that has been prepared by using an AC (Alternating Current) motor and an inverter in combination, or by using a DC (Direct Current) motor and a thyristor in combination. In this case, it becomes necessary to use an installation space for installing a controller device for controlling the inverter or thyristor, with the result that the size of the rotating machine is increased. In addition, since it is needed to maintain the temperature of the installation space (control chamber or the like) at a fixed value, it is necessary to use an air conditioner, with the result that the size of the rotating machine is further increased and in addition the facilities involved therein become high in cost. PA1 (2) Use is made of a rotating machine that has been prepared by using concurrently used AC/DC motors, hydraulic pump and hydraulic motor in combination, or by using an engine, hydraulic pump and hydraulic motor in combination. In this case, although a wide range of variable speeds is obtained, the efficiency becomes low and the power consumption increases. PA1 (1) First means is a variable speed power transmission apparatus comprising an epicycle reduction gear device that has planetary gears whose shafts are supported at equal intervals taken circumferentially thereof by carriers fixed to an output shaft thereof, the planetary gears being meshed between external teeth of a sun gear fixed to an input shaft connected to a drive source and internal teeth of a ring gear, and a variable speed hydraulic driver system that is driven by an oil pressure generated by a power of the drive source in such a way as to be variably and reversibly rotated by the oil pressure, an output shaft of the variable speed oil pressure driver system being connected to the ring gear in interlocking relation therewith to thereby cause forward rotation, reverse rotation or stoppage of the ring gear by the variable speed hydraulic driver system. PA1 (2) Second means comprises a hydraulic pump and a hydraulic motor that are used as the variable speed hydraulic driver system in the first means. The second means is a variable speed power transmission apparatus comprising an epicycle reduction gear device that has planetary gears whose shafts are supported at equal intervals taken circumferentially thereof by carriers fixed to an output shaft thereof, the planetary gears being meshed between external teeth of a sun gear fixed to an input shaft connected to a drive source and internal teeth of a ring gear, and a hydraulic driver system that includes a variable amount of discharge type hydraulic pump and a variable speed and reversible rotation type hydraulic motor that is driven by a pressure oil supplied from the hydraulic pump, an output shaft of the hydraulic motor being interlockingly connected to the ring gear by means of transmission means such as a gear to thereby cause forward rotation, reverse rotation or stoppage of the ring gear by the hydraulic motor. PA1 (3) Also, in the second means, it may be arranged to drive a rotating shaft of the hydraulic pump by a drive force that is transmitted thereto from the input shaft of the sun gear through power transmission means such as a power transmission gear. PA1 (4) Further, in the second means, it can be also arranged to connect the rotating shaft of the hydraulic pump to a second input shaft that has been provided separately from the input shaft of the epicycle reduction gear device. PA1 (5) Third means is a variable speed power transmission apparatus wherein, in the first and second means, a clutch is interposed between the input shaft of the epicycle reduction gear device and the rotating shaft of the hydraulic pump. PA1 (6) Fourth means is one of arrangements obtained by embodying the variable speed hydraulic driver system that is used in the first means and this fourth means is a variable speed power transmission apparatus comprising the epicycle reduction gear device that has planetary gears whose shafts are supported at equal intervals taken circumferentially thereof by the carriers fixed to the output shaft thereof, the planetary gears being meshed between the external teeth of the sun gear fixed to the input shaft and the internal teeth of the ring gear, and a hydraulic driver system that includes a variable amount of discharge type hydraulic pump and a variable speed and reversible rotation type hydraulic motor that is driven by a pressure oil supplied from the hydraulic pump, an output shaft of the hydraulic motor having a worm fixed thereto, the worm being meshed with a worm wheel that is connected to the ring gear, whereby the ring gear is forward rotated, reverse rotated or stopped by the hydraulic motor. PA1 (7) Fifth means is an arrangement comprising an epicycle reduction gear device that has planetary gears whose shafts are supported at equal intervals taken circumferentially thereof by carriers fixed to an output shaft thereof, the planetary gears being meshed between external teeth of a sun gear fixed to an input shaft to which a torque is input from a drive source through a transmission and internal teeth of a ring gear, and a hydraulic transmission to which the torque is input from an output end of the drive source through a transmission path that branches off from a transmission path that leads to the transmission, an output shaft of the hydraulic transmission being interlockingly connected to the ring gear by means of transmission means such as a gear to thereby cause forward rotation, reverse rotation or stoppage of the ring gear by the hydraulic transmission. PA1 (8) Sixth means is an arrangement comprising the hydraulic transmission and epicycle reduction gear device that are the same as in the fifth means and in addition thereto a worm mechanism that is composed of a worm that is connected to the output shaft of the hydraulic transmission and a worm wheel that is meshed with the worm, the worm wheel of the worm mechanism being interlockingly connected to the ring gear, whereby the ring gear is forward rotated, reverse rotated or stopped from the hydraulic transmission through the worm mechanism. PA1 (9) Seventh means is an arrangement wherein, in each of the first to sixth means, the ring gear has additionally provided thereon a brake for stopping the rotation of this ring gear. PA1 (10) As mentioned above, according to the present invention, the following effects can be procured.